The present invention relates to helicopters, and, in particular, relates to drive shafts for the transfer of power therein.
In the H-53 helicopter, a drive shaft is attached between a drive gear box and a fan to cool, for example, oil. The drive shaft may turn at rpms up to 7,000 rpms and because of this high rpm, slight imbalances at either end will cause vibrations at different amplitudes and frequencies which cause the shaft length to change. This problem in the past was addressed by the use of a male/female splined joint arrangement. In use, this joint has excessive wear and lasts only about 350 to 450 hours before replacement is required. Obviously, this is expensive and time consuming.
Thus, there exists a need for a drive shaft having a longer life.